Medium

twisted.web has disordered HTTP pipeline response

  • Disclosed: 25.10.2023
  • Updated: 11.10.2026 12:19

Twisted is an event-based framework for internet applications. Prior to version 23.10.0rc1, when sending multiple HTTP requests in one TCP packet, twisted.web will process the requests asynchronously without guaranteeing the response order. If one of the endpoints is controlled by an attacker, the attacker can delay the response on purpose to manipulate the response of the second request when a victim launched two requests using HTTP pipeline. Version 23.10.0rc1 contains a patch for this issue.

Details

There's an example faulty program:

python
from twisted.internet import reactor, endpoints
from twisted.web import server
from twisted.web.proxy import ReverseProxyResource
from twisted.web.resource import Resource

class Second(Resource):
    isLeaf = True
    def render_GET(self, request):
        return b'SECOND\n'

class First(Resource):
    isLeaf = True
    def render_GET(self, request):
        def send_response():
            request.write(b'FIRST DELAYED\n')
            request.finish()
        reactor.callLater(0.5, send_response)
        return server.NOT_DONE_YET

root = Resource()

root.putChild(b'second', Second())
root.putChild(b'first', First())

endpoint = endpoints.TCP4ServerEndpoint(reactor, 8080)
endpoint.listen(server.Site(root))
reactor.run()

When two requests for /first and /second are sent in the same order, the second request will be responded to first.

bash
echo -en "GET /first HTTP/1.1\r\nHost: a\r\n\r\nGET /second HTTP/1.1\r\nHost: a\r\n\r\n" | nc localhost 8080

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) twisted < 23.10.0rc1 23.10.0rc1

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE)
CWE-444
Platform
Python (PyPI)
Package
twisted
Disclosed
25.10.2023
Updated
11.10.2026 12:19

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2023-224 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-xc8x-vp79-p3wm - CC BY 4.0

Vulnerability history: twisted

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (17) in the archive
Total entries
17
First → latest
06.2019 10.2026
Without a fix
1
Exploited in attacks
0

Severity breakdown

  • Critical 5
  • High 4
  • Medium 8

Disclosures per year

  1. 2019: 3
  2. 2020: 3
  3. 2021: 0
  4. 2022: 6
  5. 2023: 1
  6. 2024: 2
  7. 2025: 0
  8. 2026: 2
Severity:
  1. twisted.web has disordered HTTP pipeline response this entry
    Medium · 5.3 CVE-2023-46137 < 23.10.0rc1 23.10.0rc1
  2. Critical · 8.1 CVE-2022-24801 < 22.4.0 22.4.0
  3. Critical ghsa-32gv-6cf3-wcmq < 19.10.0 19.10.0
  4. High · 7.5 CVE-2022-21716 >= 21.7.0, < 22.2.0 22.2.0
  5. High · 7.5 CVE-2022-21712 >= 11.1.0, < 22.1.0 22.1.0
  6. Critical · 9.8 CVE-2020-10109 < 20.3.0 20.3.0
  7. Critical · 9.8 CVE-2020-10108 < 20.3.0 20.3.0
  8. High · 7.5 CVE-2014-7143 >= 14.0.0, < 14.0.1 14.0.1
  9. Critical · 7.4 CVE-2019-12855 < 19.7.0rc1 19.7.0rc1

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